detachable_joint.sdf

<?xml version="1.0" ?>
<!--
  This is an example usage of the DetachableJoint system to implement breadcrumbs (devices that can be dropped while navigating a map)

  Try sending commands:

    To move the vehicle:

      gz topic -t "/model/vehicle_blue/cmd_vel" -m gz.msgs.Twist -p "linear: {x: 0.5}"

    To drop breadcrumbs:

      gz topic -t "/B1/detach" -m gz.msgs.Empty -p "unused: true"
      gz topic -t "/B2/detach" -m gz.msgs.Empty -p "unused: true"
      gz topic -t "/B3/detach" -m gz.msgs.Empty -p "unused: true"
-->

<sdf version="1.6">
  <world name="detachable_joint">

    <physics name="1ms" type="ignored">
      <max_step_size>0.001</max_step_size>
      <real_time_factor>1.0</real_time_factor>
    </physics>
    <plugin
      filename="gz-sim-physics-system"
      name="gz::sim::systems::Physics">
    </plugin>
    <plugin
      filename="gz-sim-user-commands-system"
      name="gz::sim::systems::UserCommands">
    </plugin>
    <plugin
      filename="gz-sim-scene-broadcaster-system"
      name="gz::sim::systems::SceneBroadcaster">
    </plugin>

    <light type="directional" name="sun">
      <cast_shadows>true</cast_shadows>
      <pose>0 0 10 0 0 0</pose>
      <diffuse>1 1 1 1</diffuse>
      <specular>0.5 0.5 0.5 1</specular>
      <attenuation>
        <range>1000</range>
        <constant>0.9</constant>
        <linear>0.01</linear>
        <quadratic>0.001</quadratic>
      </attenuation>
      <direction>-0.5 0.1 -0.9</direction>
    </light>

    <model name="ground_plane">
      <static>true</static>
      <link name="link">
        <collision name="collision">
          <geometry>
            <plane>
              <normal>0 0 1</normal>
              <size>100 100</size>
            </plane>
          </geometry>
        </collision>
        <visual name="visual">
          <geometry>
            <plane>
              <normal>0 0 1</normal>
              <size>100 100</size>
            </plane>
          </geometry>
          <material>
            <ambient>0.8 0.8 0.8 1</ambient>
            <diffuse>0.8 0.8 0.8 1</diffuse>
            <specular>0.8 0.8 0.8 1</specular>
          </material>
        </visual>
      </link>
    </model>

    <model name='vehicle_blue'>
      <pose>0 2 0.325 0 -0 0</pose>
      <self_collide>true</self_collide>

      <link name='chassis'>
        <pose>-0.151427 -0 0.175 0 -0 0</pose>
        <inertial>
          <mass>1.14395</mass>
          <inertia>
            <ixx>0.126164</ixx>
            <ixy>0</ixy>
            <ixz>0</ixz>
            <iyy>0.416519</iyy>
            <iyz>0</iyz>
            <izz>0.481014</izz>
          </inertia>
        </inertial>
        <visual name='visual'>
          <geometry>
            <box>
              <size>2.01142 1 0.568726</size>
            </box>
          </geometry>
          <material>
            <ambient>0.5 0.5 1.0 1</ambient>
            <diffuse>0.5 0.5 1.0 1</diffuse>
            <specular>0.0 0.0 1.0 1</specular>
          </material>
        </visual>
        <collision name='collision'>
          <geometry>
            <box>
              <size>2.01142 1 0.568726</size>
            </box>
          </geometry>
        </collision>
      </link>

      <link name='front_left_wheel'>
        <pose>0.554283 0.625029 -0.025 -1.5707 0 0</pose>
        <inertial>
          <mass>2</mass>
          <inertia>
            <ixx>0.145833</ixx>
            <ixy>0</ixy>
            <ixz>0</ixz>
            <iyy>0.145833</iyy>
            <iyz>0</iyz>
            <izz>0.125</izz>
          </inertia>
        </inertial>
        <visual name='visual'>
          <geometry>
            <sphere>
              <radius>0.3</radius>
            </sphere>
          </geometry>
          <material>
            <ambient>0.2 0.2 0.2 1</ambient>
            <diffuse>0.2 0.2 0.2 1</diffuse>
            <specular>0.2 0.2 0.2 1</specular>
          </material>
        </visual>
        <collision name='collision'>
          <geometry>
            <sphere>
              <radius>0.3</radius>
            </sphere>
          </geometry>
          <surface>
            <friction>
              <ode>
                <mu>1</mu>
                <mu2>1</mu2>
                <slip1>0.035</slip1>
                <slip2>0</slip2>
                <fdir1>0 0 1</fdir1>
              </ode>
              <bullet>
                <friction>1</friction>
                <friction2>1</friction2>
                <rolling_friction>0.1</rolling_friction>
              </bullet>
            </friction>
          </surface>
        </collision>
      </link>

      <link name='rear_left_wheel'>
        <pose>-0.957138 0.625029 -0.025 -1.5707 0 0</pose>
        <inertial>
          <mass>2</mass>
          <inertia>
            <ixx>0.145833</ixx>
            <ixy>0</ixy>
            <ixz>0</ixz>
            <iyy>0.145833</iyy>
            <iyz>0</iyz>
            <izz>0.125</izz>
          </inertia>
        </inertial>
        <visual name='visual'>
          <geometry>
            <sphere>
              <radius>0.3</radius>
            </sphere>
          </geometry>
          <material>
            <ambient>0.2 0.2 0.2 1</ambient>
            <diffuse>0.2 0.2 0.2 1</diffuse>
            <specular>0.2 0.2 0.2 1</specular>
          </material>
        </visual>
        <collision name='collision'>
          <geometry>
            <sphere>
              <radius>0.3</radius>
            </sphere>
          </geometry>
          <surface>
            <friction>
              <ode>
                <mu>1</mu>
                <mu2>1</mu2>
                <slip1>0.035</slip1>
                <slip2>0</slip2>
                <fdir1>0 0 1</fdir1>
              </ode>
              <bullet>
                <friction>1</friction>
                <friction2>1</friction2>
                <rolling_friction>0.1</rolling_friction>
              </bullet>
            </friction>
          </surface>
        </collision>
      </link>

      <link name='front_right_wheel'>
        <pose>0.554282 -0.625029 -0.025 -1.5707 0 0</pose>
        <inertial>
          <mass>2</mass>
          <inertia>
            <ixx>0.145833</ixx>
            <ixy>0</ixy>
            <ixz>0</ixz>
            <iyy>0.145833</iyy>
            <iyz>0</iyz>
            <izz>0.125</izz>
          </inertia>
        </inertial>
        <visual name='visual'>
          <geometry>
            <sphere>
              <radius>0.3</radius>
            </sphere>
          </geometry>
          <material>
            <ambient>0.2 0.2 0.2 1</ambient>
            <diffuse>0.2 0.2 0.2 1</diffuse>
            <specular>0.2 0.2 0.2 1</specular>
          </material>
        </visual>
        <collision name='collision'>
          <geometry>
            <sphere>
              <radius>0.3</radius>
            </sphere>
          </geometry>
          <surface>
            <friction>
              <ode>
                <mu>1</mu>
                <mu2>1</mu2>
                <slip1>0.035</slip1>
                <slip2>0</slip2>
                <fdir1>0 0 1</fdir1>
              </ode>
              <bullet>
                <friction>1</friction>
                <friction2>1</friction2>
                <rolling_friction>0.1</rolling_friction>
              </bullet>
            </friction>
          </surface>
        </collision>
      </link>

      <link name='rear_right_wheel'>
        <pose>-0.957138 -0.625029 -0.025 -1.5707 0 0</pose>
        <inertial>
          <mass>2</mass>
          <inertia>
            <ixx>0.145833</ixx>
            <ixy>0</ixy>
            <ixz>0</ixz>
            <iyy>0.145833</iyy>
            <iyz>0</iyz>
            <izz>0.125</izz>
          </inertia>
        </inertial>
        <visual name='visual'>
          <geometry>
            <sphere>
              <radius>0.3</radius>
            </sphere>
          </geometry>
          <material>
            <ambient>0.2 0.2 0.2 1</ambient>
            <diffuse>0.2 0.2 0.2 1</diffuse>
            <specular>0.2 0.2 0.2 1</specular>
          </material>
        </visual>
        <collision name='collision'>
          <geometry>
            <sphere>
              <radius>0.3</radius>
            </sphere>
          </geometry>
          <surface>
            <friction>
              <ode>
                <mu>1</mu>
                <mu2>1</mu2>
                <slip1>0.035</slip1>
                <slip2>0</slip2>
                <fdir1>0 0 1</fdir1>
              </ode>
              <bullet>
                <friction>1</friction>
                <friction2>1</friction2>
                <rolling_friction>0.1</rolling_friction>
              </bullet>
            </friction>
          </surface>
        </collision>
      </link>


      <joint name='front_left_wheel_joint' type='revolute'>
        <parent>chassis</parent>
        <child>front_left_wheel</child>
        <axis>
          <xyz>0 0 1</xyz>
          <limit>
            <lower>-1.79769e+308</lower>
            <upper>1.79769e+308</upper>
          </limit>
        </axis>
      </joint>

      <joint name='front_right_wheel_joint' type='revolute'>
        <parent>chassis</parent>
        <child>front_right_wheel</child>
        <axis>
          <xyz>0 0 1</xyz>
          <limit>
            <lower>-1.79769e+308</lower>
            <upper>1.79769e+308</upper>
          </limit>
        </axis>
      </joint>

      <joint name='rear_left_wheel_joint' type='revolute'>
        <parent>chassis</parent>
        <child>rear_left_wheel</child>
        <axis>
          <xyz>0 0 1</xyz>
          <limit>
            <lower>-1.79769e+308</lower>
            <upper>1.79769e+308</upper>
          </limit>
        </axis>
      </joint>

      <joint name='rear_right_wheel_joint' type='revolute'>
        <parent>chassis</parent>
        <child>rear_right_wheel</child>
        <axis>
          <xyz>0 0 1</xyz>
          <limit>
            <lower>-1.79769e+308</lower>
            <upper>1.79769e+308</upper>
          </limit>
        </axis>
      </joint>

      <plugin
        filename="gz-sim-diff-drive-system"
        name="gz::sim::systems::DiffDrive">
        <left_joint>front_left_wheel_joint</left_joint>
        <left_joint>rear_left_wheel_joint</left_joint>
        <right_joint>front_right_wheel_joint</right_joint>
        <right_joint>rear_right_wheel_joint</right_joint>
        <wheel_separation>1.25</wheel_separation>
        <wheel_radius>0.3</wheel_radius>
      </plugin>
      <plugin filename="gz-sim-detachable-joint-system" name="gz::sim::systems::DetachableJoint">
       <parent_link>chassis</parent_link>
       <child_model>B1</child_model>
       <child_link>body</child_link>
       <topic>/B1/detach</topic>
      </plugin>
      <plugin filename="gz-sim-detachable-joint-system" name="gz::sim::systems::DetachableJoint">
       <parent_link>chassis</parent_link>
       <child_model>B2</child_model>
       <child_link>body</child_link>
       <topic>/B2/detach</topic>
      </plugin>
      <plugin filename="gz-sim-detachable-joint-system" name="gz::sim::systems::DetachableJoint">
       <parent_link>chassis</parent_link>
       <child_model>B3</child_model>
       <child_link>body</child_link>
       <topic>/B3/detach</topic>
      </plugin>
    </model>

    <model name="B1">
       <!-- Setting the pose to
          <pose> -1.3 2.35 0.5 0 -0 0 </pose>
        will cause Gazebo to crash because B1 will be in collision with vehicle_blue while in the attached state-->
      <pose>-1.5 2.35 0.5 0 -0 0</pose>
      <link name='body'>
        <inertial>
          <mass>0.6</mass>
          <inertia>
            <ixx>0.017</ixx>
            <ixy>0</ixy>
            <ixz>0</ixz>
            <iyy>0.017</iyy>
            <iyz>0</iyz>
            <izz>0.009</izz>
          </inertia>
        </inertial>
        <visual name='visual'>
          <geometry>
            <box>
              <size>0.3 0.3 0.5</size>
            </box>
          </geometry>
          <material>
            <ambient>0.0 1.0 0.0 1</ambient>
            <diffuse>0.0 1.0 0.0 1</diffuse>
            <specular>0.5 0.5 0.5 1</specular>
          </material>
        </visual>
        <collision name='collision'>
          <geometry>
            <box>
              <size>0.3 0.3 0.5</size>
            </box>
          </geometry>
        </collision>
      </link>
    </model>
    <model name="B2">
      <pose>-1.5 2 0.5 0 -0 0</pose>
      <link name='body'>
        <inertial>
          <mass>0.6</mass>
          <inertia>
            <ixx>0.017</ixx>
            <ixy>0</ixy>
            <ixz>0</ixz>
            <iyy>0.017</iyy>
            <iyz>0</iyz>
            <izz>0.009</izz>
          </inertia>
        </inertial>
        <visual name='visual'>
          <geometry>
            <box>
              <size>0.3 0.3 0.5</size>
            </box>
          </geometry>
          <material>
            <ambient>1 1 0 1</ambient>
            <diffuse>1 1 0 1</diffuse>
            <specular>0.5 0.5 0.5 1</specular>
          </material>
        </visual>
        <collision name='collision'>
          <geometry>
            <box>
              <size>0.3 0.3 0.5</size>
            </box>
          </geometry>
        </collision>
      </link>
    </model>
    <model name="B3">
      <pose>-1.5 1.65 0.5 0 -0 0</pose>
      <link name='body'>
        <inertial>
          <mass>0.6</mass>
          <inertia>
            <ixx>0.017</ixx>
            <ixy>0</ixy>
            <ixz>0</ixz>
            <iyy>0.017</iyy>
            <iyz>0</iyz>
            <izz>0.009</izz>
          </inertia>
        </inertial>
        <visual name='visual'>
          <geometry>
            <box>
              <size>0.3 0.3 0.5</size>
            </box>
          </geometry>
          <material>
            <ambient>1.0 0.0 0.0 1</ambient>
            <diffuse>1.0 0.0 0.0 1</diffuse>
            <specular>0.5 0.5 0.5 1</specular>
          </material>
        </visual>
        <collision name='collision'>
          <geometry>
            <box>
              <size>0.3 0.3 0.5</size>
            </box>
          </geometry>
        </collision>
      </link>
  </model>
</world>
</sdf>